Microcrystal laser for generating laser pulses

Abstract

A microcrystal laser for generating laser pulses has a laser resonator which has a laser medium arranged between two mirrors; and an arrangement for stabilizing the optical path length is provided. The laser resonator has a saturable absorber medium for pulse generation.

What is claimed is: 
     
       1. A laser apparatus comprising:
 a solid state gain medium; 
 a first mirror spaced from the solid state gain medium to define an air gap and wherein the first mirror is a saturable absorber and wherein said solid state gain medium includes a partly reflecting coating locating on the side of the solid state gain medium opposite to the first mirror, said partly reflecting coating defining an output coupler and wherein the first mirror and the output coupler define an optical resonator; 
 a first carrier for supporting the solid state gain medium; 
 a second carrier for supporting the first mirror; and 
 a spacer extending across said air gap and being connected to both said first and second carriers, said spacer having a coefficient of thermal expansion selected so that when a temperature of the laser is changed, the width of the air gap will vary in a manner to adjust an optical path length of the optical resonator. 
 
     
     
       2. A laser as recited in  claim 1 , wherein the gain medium is excited by directing pump light through the output coupler. 
     
     
       3. A laser as recited in  claim 2 , wherein a second coating is provided on one of (1) the side of the solid state gain medium facing the saturable absorber or (2) the side of the saturable absorber facing the solid state gain medium, said second coating for reflecting pump light back into the solid state gain medium. 
     
     
       4. A laser as recited in  claim 1 , further including a control device for monitoring the output of the laser and in response thereto varying the temperature of the laser in order to vary the optical path length of the resonator. 
     
     
       5. A laser as recited in  claim 1 , wherein a geometrical path length of the optical resonator is less than 500 μm. 
     
     
       6. A laser as recited in  claim 1 , wherein the coefficient of thermal expansion of the spacer is higher than the coefficient of thermal expansion of the saturable absorber so that when the temperature of the laser is increased the optical path length of the optical resonator will increase. 
     
     
       7. A laser apparatus comprising:
 a solid state gain medium, 
 a first mirror spaced from the solid state gain medium to define an air gap and wherein the first mirror is a saturable absorber; 
 an output coupler positioned on the side of the solid state gain medium opposite the first mirror, and wherein the first mirror and the output coupler define an optical resonator; 
 a diode laser generating pump light, said pump light being directed into the solid state gain medium through said output coupler and wherein a coating is provided on one of (1) the side of the solid state gain medium facing the saturable absorber or (2) the side of the saturable absorber facing the gain medium, said coating for reflecting pump light back into the solid state gain medium; 
 a first carrier for supporting the solid state gain medium; 
 a second carrier for supporting the first mirror; and 
 a spacer extending across said air gap and being connected to both said first and second carriers, said spacer having a coefficient of thermal expansion selected so that when a temperature of the laser is changed, the width of the air gap will vary in a manner to adjust an optical path length of the optical resonator. 
 
     
     
       8. A laser as recited in  claim 7 , further including a control device for monitoring the output of the laser and in response thereto varying the temperature of the laser in order to vary the optical path length of the resonator. 
     
     
       9. A laser as recited in  claim 7 , wherein a geometrical path length of the optical resonator is less than 500 μm. 
     
     
       10. A laser as recited in  claim 7 , wherein the coefficient of thermal expansion of the spacer is higher than a coefficient of thermal expansion of the saturable absorber so that when the temperature of the laser is increased the optical path length of the optical resonator will increase.